U.S. patent application number 15/763218 was filed with the patent office on 2018-09-27 for solid-state imaging device, and method of manufacturing solid-state imaging device.
This patent application is currently assigned to SONY SEMICONDUCTOR SOLUTIONS CORPORATION. The applicant listed for this patent is SONY SEMICONDUCTOR SOLUTIONS CORPORATION. Invention is credited to MASAHIRO JOEI.
Application Number | 20180277604 15/763218 |
Document ID | / |
Family ID | 58487466 |
Filed Date | 2018-09-27 |
United States Patent
Application |
20180277604 |
Kind Code |
A1 |
JOEI; MASAHIRO |
September 27, 2018 |
SOLID-STATE IMAGING DEVICE, AND METHOD OF MANUFACTURING SOLID-STATE
IMAGING DEVICE
Abstract
A solid-state imaging device includes: a plurality of pixels
each including a first electrode, an organic photoelectric
conversion film, and a second electrode in this order on a
substrate, the organic photoelectric conversion film including a
first inclined surface on a side wall; and a first sealing film
formed, on the plurality of pixels, to cover the side wall of the
organic photoelectric conversion film and the second electrode.
Inventors: |
JOEI; MASAHIRO; (KANAGAWA,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SONY SEMICONDUCTOR SOLUTIONS CORPORATION |
KANAGAWA |
|
JP |
|
|
Assignee: |
SONY SEMICONDUCTOR SOLUTIONS
CORPORATION
KANAGAWA
JP
|
Family ID: |
58487466 |
Appl. No.: |
15/763218 |
Filed: |
August 18, 2016 |
PCT Filed: |
August 18, 2016 |
PCT NO: |
PCT/JP2016/074075 |
371 Date: |
March 26, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 27/307 20130101;
H01L 27/286 20130101; H01L 27/281 20130101; H04N 9/045 20130101;
H01L 51/4273 20130101; Y02P 70/50 20151101; H01L 27/146 20130101;
H01L 51/4293 20130101; H01L 27/14645 20130101; H01L 51/442
20130101; H01L 27/14667 20130101; Y02E 10/549 20130101; H04N 5/369
20130101; H01L 51/448 20130101; H01L 51/0072 20130101 |
International
Class: |
H01L 27/30 20060101
H01L027/30; H01L 51/44 20060101 H01L051/44; H01L 51/42 20060101
H01L051/42; H01L 27/28 20060101 H01L027/28 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 6, 2015 |
JP |
2015-198578 |
Claims
1. A solid-state imaging device, comprising: a plurality of pixels
each including a first electrode, an organic photoelectric
conversion film, and a second electrode in this order on a
substrate, the organic photoelectric conversion film including a
first inclined surface on a side wall; and a first sealing film
formed, on the plurality of pixels, to cover the side wall of the
organic photoelectric conversion film and the second electrode.
2. The solid-state imaging device according to claim 1, wherein a
plurality of the first electrodes are provided on the substrate,
and the organic photoelectric conversion film is continuously
formed as a layer common to the plurality of first electrodes.
3. The solid-state imaging device according to claim 1, wherein the
second electrode includes a second inclined surface on a side wall
thereof.
4. The solid-state imaging device according to claim 3, wherein the
second inclined surface has an inclination angle equal to or lower
than an inclination angle of the first inclined surface.
5. The solid-state imaging device according to claim 1, wherein the
first sealing film is formed in contact with the side wall of the
organic photoelectric conversion film.
6. The solid-state imaging device according to claim 1, further
comprising a second sealing film between the side wall of the
organic photoelectric conversion film and the first sealing
film.
7. The solid-state imaging device according to claim 1, wherein a
plurality of the first electrodes and a plurality of the organic
photoelectric conversion films are formed, and a third sealing film
having a refractive index lower than a refractive index of the
first sealing film is further included in a region between the side
walls of the organic photoelectric conversion films adjacent to
each other.
8. The solid-state imaging device according to claim 1, wherein the
second electrode is continuously formed over a region facing a top
surface and a region facing the side wall of the organic
photoelectric conversion film.
9. The solid-state imaging device according to claim 8, wherein a
plurality of the first electrodes and a plurality of the organic
photoelectric conversion films are formed, and the second electrode
is provided for each of the organic photoelectric conversion
films.
10. The solid-state imaging device according to claim 8, wherein a
plurality of the first electrodes and a plurality of the organic
photoelectric conversion films are formed, and the second electrode
is continuously provided as a layer common to the organic
photoelectric conversion films.
11. The solid-state imaging device according to claim 1, wherein
the organic photoelectric conversion film contains one or more of
quinacridone, subphthalocyanine, or derivatives thereof.
12. The solid-state imaging device according to claim 1, wherein
the substrate includes a semiconductor layer that includes one or
two or more photoelectric conversion devices.
13. A method of manufacturing a solid-state imaging device, the
method comprising: a process of forming a plurality of pixels each
including a first electrode, an organic photoelectric conversion
film, and a second electrode in this order on a substrate, the
organic photoelectric conversion film including a first inclined
surface on a side wall; and a process of forming a first sealing
film, on the plurality of pixels, to cover the side wall of the
organic photoelectric conversion film and the second electrode.
14. The method of manufacturing the solid-state imaging device
according to claim 13, wherein after the organic photoelectric
conversion film and the second electrode are formed in this order,
the formed organic photoelectric conversion film and the formed
second electrode are collectively processed to form the first
inclined surface on the side wall of the organic photoelectric
conversion film, and to form a second inclined surface on a side
wall of the second electrode.
15. The method of manufacturing the solid-state imaging device
according to claim 13, wherein the first sealing film is formed
with use of an Atomic Layer Deposition (ALD) method, a Chemical
Vapor Deposition (CVD) method, or a Physical Vapor Deposition (PVD)
method.
16. A solid-state imaging device, comprising: a plurality of pixels
each including a first electrode, an organic photoelectric
conversion film, and a second electrode in this order on a
substrate; a first sealing film formed, on the plurality of pixels,
to cover a side wall of the organic photoelectric conversion film
and the second electrode; and a second sealing film formed between
the side wall of the organic photoelectric conversion film and the
first sealing film.
17. The solid-state imaging device according to claim 16, wherein
the second sealing film is formed in contact with the side wall of
the organic photoelectric conversion film and a side wall of the
second electrode.
18. A solid-state imaging device, comprising: a plurality of pixels
each including a first electrode, an organic photoelectric
conversion film, and a second electrode in this order on a
substrate; and a first sealing film formed on the plurality of
pixels, wherein a plurality of the organic photoelectric conversion
films are disposed separately for the respective pixels, and a
third sealing film is formed to fill a region between side walls of
the organic photoelectric conversion films adjacent to each
other.
19. The solid-state imaging device according to claim 18, wherein
the third sealing film has a refractive index lower than a
refractive index of the first sealing film.
20. The solid-state imaging device according to claim 19, wherein
the third sealing film contains one or more of aluminum oxide
(AlO.sub.x), carbon-containing silicon oxide (SiOC), tungsten (W),
and aluminum (Al).
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a solid-state imaging
device such as a CCD (Charge Coupled Device) image sensor and a
CMOS (Complementary Metal Oxide Semiconductor) image sensor, and to
a method of manufacturing the solid-state imaging device.
BACKGROUND ART
[0002] In recent years, in a solid-state imaging device such as a
CCD image sensor and a CMOS image sensor, the number of photons
entering a unit pixel is decreased with reduction of a pixel size,
which deteriorates sensitivity and an S/N ratio as a result.
Further, in such a solid-state imaging device, pixels of three
primary colors are often two-dimensionally arranged typically with
use of color filters of primary colors of red, green, blue, or
other colors. In a case where the color filters are used, however,
optical loss occurs to deteriorate sensitivity. For example, in a
red pixel, green light and blue light are not photoelectrically
converted because the green light and the blue light do not pass
through the color filters, which causes optical loss as a result.
Moreover, signals of respective colors are generated by
interpolation processing between pixels, which generates so-called
false colors.
[0003] Accordingly, a solid-state imaging device in which three
photoelectric conversion layers of red, green, and blue are stacked
in a vertical direction and photoelectric conversion signals of
three colors are obtainable from one pixel has been proposed (e.g.,
PTLs 1 and 2). PTL 1 proposes a structure in which an organic
photoelectric conversion film that absorbs green light to generate
signal charges is provided above a silicon substrate, and two
inorganic photoelectric converters (photodiodes) that detect blue
light and red light are stacked in the silicon substrate. In
addition, PTL 2 proposes a so-called back-illuminated device
structure in which a light receiving surface is provided on side
opposite to a circuit formation surface of the silicon substrate in
such a structure in which the organic photoelectric conversion film
respectively provided above the silicon substrate and the silicon
substrate.
[0004] In the above-described solid-state imaging device including
the organic photoelectric conversion film, it is desirable to form
a sealing film in order to prevent moisture, etc. from entering the
pixel (e.g., PTL 3).
CITATION LIST
Patent Literature
[0005] PTL 1: Japanese Unexamined Patent Application Publication
No. 2003-332551
[0006] PTL 2: Japanese Unexamined Patent Application Publication
No. 2011-29337
[0007] PTL 3: Japanese Unexamined Patent Application Publication
No. 2015-56554
SUMMARY OF INVENTION
[0008] In the method disclosed in PTL 3 described above, however,
it is not possible to sufficiently secure coverage of the sealing
film, and moisture, etc. infiltrates into the organic photoelectric
conversion film to deteriorate photoelectric conversion
characteristics.
[0009] It is desirable to provide a solid-state imaging device that
makes it possible to secure sealing performance to suppress
deterioration of photoelectric conversion characteristics and a
method of manufacturing the solid-state imaging device.
[0010] A first solid-state imaging device according to an
embodiment of the present disclosure includes: a plurality of
pixels each including a first electrode, an organic photoelectric
conversion film, and a second electrode in this order on a
substrate, the organic photoelectric conversion film including a
first inclined surface on a side wall; and a first sealing film
formed, on the plurality of pixels, to cover the side wall of the
organic photoelectric conversion film and the second electrode.
[0011] A method of manufacturing a solid-state imaging device
according to an embodiment of the present disclosure includes: a
process of forming a plurality of pixels each including a first
electrode, an organic photoelectric conversion film, and a second
electrode in this order on a substrate, the organic photoelectric
conversion film including a first inclined surface on a side wall;
and a process of forming a first sealing film, on the plurality of
pixels, to cover the side wall of the organic photoelectric
conversion film and the second electrode.
[0012] In the first solid-state imaging device according to the
embodiment of the present disclosure, the organic photoelectric
conversion film includes the first inclined surface on the side
wall in each of the plurality of pixels. The first sealing film is
formed, on the plurality of pixels, to cover the side wall of the
organic photoelectric conversion film and the second electrode. In
this case, coverage of the first sealing film to the side wall of
the organic photoelectric conversion film may become lower due to
the film formation process; however, the side wall includes the
first inclined surface, which improves the coverage of the first
sealing film. This suppresses infiltration of moisture from the
side wall of the organic photoelectric conversion film.
[0013] In the method of manufacturing the solid-state imaging
device according to the embodiment of the present disclosure, the
first sealing film is formed to cover the side wall of the organic
photoelectric conversion film including the first inclined surface
on the side wall and the second electrode. In this case, in the
formation of the first sealing film, coverage of the first sealing
film to the side wall of the organic photoelectric conversion film
may become lower due to the film formation process; however, the
side wall includes the first inclined surface, which improves the
coverage of the first sealing film. This suppresses infiltration of
moisture from the side wall of the organic photoelectric conversion
film.
[0014] A second solid-state imaging device according to an
embodiment of the present disclosure includes: a plurality of
pixels each including a first electrode, an organic photoelectric
conversion film, and a second electrode in this order on a
substrate; a first sealing film formed, on the plurality of pixels,
to cover a side wall of the organic photoelectric conversion film
and the second electrode; and a second sealing film formed between
the side wall of the organic photoelectric conversion film and the
first sealing film.
[0015] In the second solid-state imaging device according to the
embodiment of the present disclosure, the first sealing film is
formed, on the plurality of pixels including the organic
photoelectric conversion film, to cover the side wall of the
organic photoelectric conversion film and the second electrode, and
the second sealing film is formed between the first sealing film
and the side wall of the organic photoelectric conversion film. In
this case, coverage of the first sealing film to the side wall of
the organic photoelectric conversion film may become lower due to
the film formation process; however, interposition of the second
sealing film suppresses infiltration of moisture from the side
wall.
[0016] A third solid-state imaging device according to an
embodiment of the present disclosure includes: a plurality of
pixels each including a first electrode, an organic photoelectric
conversion film, and a second electrode in this order on a
substrate; and a first sealing film formed on the plurality of
pixels. A plurality of the organic photoelectric conversion films
are disposed separately for the respective pixels, and a third
sealing film is formed to fill a region between side walls of the
organic photoelectric conversion films adjacent to each other.
[0017] In the third solid-state imaging device according to the
embodiment of the present disclosure, the first sealing film is
formed on the plurality of pixels each including the organic
photoelectric conversion film, and the third sealing film is formed
to fill the region between the side wall of the organic
photoelectric conversion films adjacent to each other. In this
case, coverage of the first sealing film to the side walls of the
organic photoelectric conversion films may become lower due to the
film formation process; however, the above-described third sealing
film is formed, which suppresses infiltration of moisture from the
side walls of the respective organic photoelectric conversion films
even in a case where the organic photoelectric conversion films are
separated for the respective pixels.
[0018] According to the first solid-state imaging device and the
method of manufacturing the solid-state imaging device of the
respective embodiments of the present disclosure, the organic
photoelectric conversion film includes the first inclined surface
on the side wall in each of the plurality of pixels, and the first
sealing film is formed, on the plurality of pixels, to cover the
side wall of the organic photoelectric conversion film and the
second electrode. This makes it possible to improve the coverage of
the first sealing film and to suppress infiltration of moisture
from the side wall of the organic photoelectric conversion film in
a portion facing the side wall of the organic photoelectric
conversion film. As a result, it is possible to secure sealing
performance to suppress deterioration of the photoelectric
conversion characteristics.
[0019] According to the second solid-state imaging device of the
embodiment of the present disclosure, the first sealing film is
formed, on the plurality of pixels including the organic
photoelectric conversion film, to cover the side wall of the
organic photoelectric conversion film and the second electrode, and
the second sealing film is formed between the first sealing film
and the side wall of the organic photoelectric conversion film.
Interposition of the second sealing film makes it possible to
suppress infiltration of moisture from the side wall of the organic
photoelectric conversion film. As a result, it is possible to
secure sealing performance to suppress deterioration of the
photoelectric conversion characteristics.
[0020] According to the third solid-state imaging device of the
embodiment of the present disclosure, the first sealing film is
formed on the plurality of pixels each including the organic
photoelectric conversion film, and the third sealing film is formed
to fill the region between the side walls of the organic
photoelectric conversion films adjacent to each other. This makes
it possible to suppress infiltration of moisture from the side
walls of the organic photoelectric conversion films. As a result,
it is possible to secure sealing performance to suppress
deterioration of the photoelectric conversion characteristics.
[0021] Note that the above-described contents are examples of the
present disclosure. The effects achieved by the present disclosure
are not limited to those described above, and other different
effects may be achieved or other effects may be further
included.
BRIEF DESCRIPTION OF DRAWINGS
[0022] FIG. 1 is a cross-sectional view of a configuration of a
solid-state imaging device according to a first embodiment of the
present disclosure.
[0023] FIG. 2 is a characteristic diagram illustrating relationship
between an inclination angle of an inclined surface of an organic
photoelectric conversion film and sealing property.
[0024] FIG. 3 is a schematic plan view to explain a film formation
region of the organic photoelectric conversion film and an
effective pixel region.
[0025] FIG. 4 is a flowchart illustrating an example of a method of
manufacturing the solid-state imaging device illustrated in FIG.
1.
[0026] FIG. 5 is a cross-sectional schematic diagram illustrating a
configuration of a solid-state imaging device according to a
comparative example.
[0027] FIG. 6A is a cross-sectional schematic diagram illustrating
a configuration of an organic photoelectric conversion film and a
second electrode of a solid-state imaging device according to a
modification example 1-1.
[0028] FIG. 6B is a cross-sectional schematic diagram illustrating
a configuration of an organic photoelectric conversion film and a
second electrode of a solid-state imaging device according to a
modification example 1-2.
[0029] FIG. 7 is a cross-sectional schematic diagram illustrating a
configuration of a main part of a solid-state imaging device
according to a modification example 2.
[0030] FIG. 8 is a cross-sectional view of a configuration of a
solid-state imaging device according to a second embodiment of the
present disclosure.
[0031] FIG. 9A is a cross-sectional schematic diagram illustrating
a configuration of a main part of a solid-state imaging device
according to a modification example 3-1.
[0032] FIG. 9B is a cross-sectional schematic diagram illustrating
a configuration of a main part of a solid-state imaging device
according to a modification example 3-2.
[0033] FIG. 9C is a cross-sectional schematic diagram illustrating
a configuration of a main part of a solid-state imaging device
according to a modification example 3-3.
[0034] FIG. 10 is a cross-sectional view of a configuration of a
solid-state imaging device according to a third embodiment of the
present disclosure.
[0035] FIG. 11 is a cross-sectional view of a configuration of a
solid-state imaging device according to a modification example
4.
[0036] FIG. 12 is a cross-sectional view of a configuration of a
solid-state imaging device according to a modification example
5.
[0037] FIG. 13 is a block diagram illustrating a configuration of
an imaging apparatus to which the solid-state imaging device
illustrated in FIG. 1 is applied.
[0038] FIG. 14 is a schematic diagram illustrating a configuration
example of the imaging apparatus illustrated in FIG. 13.
[0039] FIG. 15 is a functional block diagram illustrating an
example of an application example (camera).
MODES FOR CARRYING OUT THE INVENTION
[0040] Embodiments of the present disclosure are described in
detail below with reference to drawings. Note that description
order is as follows.
1. First embodiment (an example of a solid-state imaging device
including an inclined surface on a side wall of an organic
photoelectric conversion film) 2. Modification examples 1-1 and 1-2
(examples in which an inclination angle of the side wall of the
organic photoelectric conversion film and an inclination angle of a
side wall of a second electrode are different from each other) 3.
Modification example 2 (an example in which a plurality of organic
photoelectric conversion films are formed separately for respective
pixels) 4. Second embodiment (an example of a solid-state imaging
device including a second sealing film between a side wall of an
organic photoelectric conversion film and a first sealing film) 5.
Modification examples 3-1 to 3-3 (other configuration examples
including the second sealing film) 6. Third embodiment (an example
of a solid-state imaging device including a third sealing film
between side walls of organic photoelectric conversion films
adjacent to each other) 7. Modification example 4 (an example in
which a second electrode is formed to face side walls and top
surfaces of organic photoelectric conversion films formed for
respective pixels) 8. Modification example 5 (an example in which
the second electrode is continuously formed as a layer common to
organic photoelectric conversion films) 9. Application example 1
(an example of an entire imaging apparatus) 10. Application example
2 (an example of a camera)
First Embodiment
Configuration
[0041] FIG. 1 illustrates a cross-sectional configuration of a
solid-state imaging device 1 according to a first embodiment of the
present disclosure. The solid-state imaging device 1 is applied to,
for example, a CCD or CMOS image sensor, etc.
[0042] In the solid-state imaging device 1, a plurality of pixels P
are two-dimensionally arranged. Each of the pixels P includes a
first electrode 13, an organic photoelectric conversion film 14,
and a second electrode 15 on a semiconductor substrate 11
(substrate) with an interlayer insulation film 12 in between. A
first sealing film 16 (first sealing film) is formed on the
plurality of pixels P to cover the organic photoelectric conversion
film 14 and the second electrode. An unillustrated protection film
(or planarization film) and an unillustrated on-chip lens are
formed on the first sealing film 16.
[0043] The solid-state imaging device 1 includes, for example, a
structure in which photoelectric conversion devices are arranged
along a vertical direction. The photoelectric conversion devices
selectively detect light of different wavelength ranges and perform
photoelectric conversion. Specifically, in the solid-state imaging
device 1, the above-described organic photoelectric conversion film
14 is formed above the semiconductor substrate 11, and
photoelectric conversion devices 110B and 110R (photodiodes) using,
for example, an inorganic semiconductor are formed in the
semiconductor substrate 11. In one pixel P, the stacked-layer
structure of the organic photoelectric conversion film 14 and the
photoelectric conversion devices 110B and 110R makes it possible to
disperse, for example, color light of red (R), green (G), and blue
(B) without using a color filter, and it is possible to obtain a
plurality of kinds (here, three kinds of R, G, and B) of color
signals from one pixel P.
[0044] The semiconductor substrate 11 includes a semiconductor
layer 11a including, for example, silicon (Si), etc. on a front
surface side, and, for example, the above-described photoelectric
conversion devices 110B and 110R are embedded in the semiconductor
layer 11a. For example, the photoelectric conversion devices 110B
and 110R are each a photodiode including a pn junction, and are
formed in order of the photoelectric conversion devices 110B and
110R from light entering side (surface S1 side). A supporting
substrate 11c is provided, with a multilayer wiring layer 11b in
between, on a surface S2 side opposite to the surface S1 of the
semiconductor layer 11a. For example, a plurality of pixel
transistors and logic circuits such as peripheral circuits are
provided as driving devices to perform signal reading from the
respective pixels P, on the surface S2 of the semiconductor layer
11a and the multilayer wiring layer 11b. Examples of the pixel
transistor include a transfer transistor (TRF), a reset transistor
(RST), an amplification transistor (AMP), a selection transistor
(SEL), etc.
[0045] The photoelectric conversion device 110B selectively
absorbs, for example, blue light (e.g., wavelength of 450 nm to 495
nm) to generate electric charges. The photoelectric conversion
device 110R selectively absorbs, for example, red light (e.g.,
wavelength of 620 nm to 750 nm) to generate electric charges. These
photoelectric conversion devices 110B and 110R each are coupled to
the above-described transfer transistor through an unillustrated
floating diffusion (FD).
[0046] A charge accumulation layer 112 that accumulates signal
charges generated by the organic photoelectric conversion film 14
is formed in the semiconductor substrate 11 (semiconductor layer
11a). The charge accumulation layer 112 is, for example, an n-type
or p-type impurity diffusion layer, and is electrically coupled to,
for example, the first electrode 13. Specifically, the charge
accumulation layer 112 and the first electrode 13 are coupled to
each other through a wiring 111. As a result, for example, the
signal charges collected in the first electrode 13 are accumulated
in the charge accumulation layer 112, and then transferred to an
unillustrated signal readout circuit through the transfer
transistor Tr.
[0047] The interlayer insulation film 12 includes one or a
plurality of insulation films. The interlayer insulation film 12
desirably has a small interface level, for example, in order to
reduce an interface level with the semiconductor layer 11a (Si) and
to suppress occurrence of a dark current from an interface between
the interlayer insulation film 12 and the semiconductor layer 11a.
In this case, insulation films 121 and 122 formed on the
semiconductor layer 11a are stacked. The insulation film 121 is a
hafnium oxide (HfO.sub.2) film formed through, for example, an ALD
(atomic layer deposition) method, and the insulation film 122 is a
silicon oxide (SiO.sub.2) film formed through, for example, a
plasma CVD method. The structure and the formation method of the
interlayer insulation film 12, however, are not limited thereto.
The insulation film 122 also has a role of electrically separating
the first electrodes 13 adjacent to each other.
[0048] The wiring 111 electrically couples the charge accumulation
layer 112 and the first electrode 13 to each other. The wiring 111
may be used as a light shielding film through patterning in a plan
view. In a case where the wiring 111 functions as the light
shielding film while securing the electric coupling with silicon,
it is possible to use, for example, a combination of a
stacked-layer film of titanium (Ti) and titanium nitride (TiN) as
barrier metals and tungsten (W) for the wiring 111.
[0049] The first electrodes 13 are provided, for example, for the
respective pixels (a plurality of first electrodes 13 are provided
on semiconductor substrate 11). The plurality of first electrodes
13 are electrically separated between adjacent pixels P by the
interlayer insulation film 12. The electric charges (e.g., holes or
electrons) are read out as the signal charges through the first
electrodes 13. As described above, the first electrodes 13 are
electrically coupled to the charge accumulation layers 112 formed
in the semiconductor substrate 11. The first electrodes 13 each
include an electroconductive film (transparent electroconductive
film) transparent to visible light in this case. Examples of the
transparent electroconductive film include ITO (indium tin oxide).
As the constituent material of the first electrodes 13, however, a
tin oxide material prepared by adding a dopant to tin oxide
(SnO.sub.2) or a zinc oxide material prepared by adding a dopant to
zinc oxide (ZnO) may be used in addition to ITO. Examples of the
zinc oxide material include aluminum zinc oxide (AZO) added with
aluminum (Al) as a dopant, a gallium zinc oxide (GZO) added with
gallium (Ga), and an indium zinc oxide (IZO) added with indium
(In). In addition, it is possible to use IGZP, CuI, InSbO.sub.4,
ZnMgO, CuInO.sub.2, MgIn.sub.2O.sub.4, CdO, ZnSnO.sub.3, etc.
[0050] The organic photoelectric conversion film 14 includes an
organic semiconductor that absorbs light of a selective wavelength
(e.g., green light having wavelength of about 495 nm to about 570
nm), to generate electron-hole pairs. The organic photoelectric
conversion film 14 is continuously provided as a layer common to
the plurality of first electrodes 13 in this case. The first
electrode 13 and the second electrode 15 are provided as a pair of
electrodes to extract the electric charges from the organic
photoelectric conversion film 14.
[0051] The organic photoelectric conversion film 14 includes one or
both of p-type and n-type organic semiconductors. Examples of the
preferred structure of the organic photoelectric conversion film 14
include a so-called p-i-n bulk hetero-structure that includes a
p-type blocking layer 14p, a co-vapor deposition layer 14i
containing p-type and n-type materials, and an n-type blocking
layer 14n in order from the first electrodes 13 side.
[0052] Examples of the organic semiconductor include quinacridone
(including quinacridone derivative). The organic semiconductor used
in the organic photoelectric conversion film 14, however, is not
limited thereto, and it is possible to use various organic
semiconductors as described below. For example, one or more of
subphthalocyanine, naphthalene, anthracene, phenanthrene,
tetracene, pyrene, perylene, fluoranthene, and the like (each
including derivative thereof) may be used. Alternatively, a polymer
or a derivative of phenylenevinylene, fluorene, carbazole, indole,
pyrene, pyrrole, picoline, thiophene, acetylene, diacetylene, and
the like may be used. In addition, metal complex dyes,
cyanine-based dyes, merocyanine-based dyes, phenylxanthene-based
dyes, triphenylmethane-based dyes, rhodacyanine-based dyes,
xanthene-based dyes, macrocyclic aza-annulene-based dyes,
azulene-based dyes, naphthoquinone-based dyes, anthraquinone-based
dyes, chain compounds obtained by condensation between condensed
polycyclic aromatic compounds, such as anthracene and pyrene, and
aromatic or hetero ring compounds, two nitrogen-containing
heterocyclic rings, such as quinolone, benzothiazole, and
benzooxazole, having a squarylium group and a croconic methine
group as bonding chains, and cyanine analogue dyes bonded by a
squarylium group and a croconic methine group may be used. Note
that examples of the metal complex dyes include dithiol metal
complex dyes, metal phthalocyanine dyes, metal porphyrin dyes, and
ruthenium complex dyes. Further, the organic photoelectric
conversion film 14 may contain, for example, fullerene (C60) and
BCP (Bathocuproine), in addition to the above-described
materials.
[0053] The second electrode 15 includes an electroconductive film
(transparent electroconductive film) transparent to visible light.
Examples of the transparent electroconductive film include ITO
(indium tin oxide). As the constituent material of the second
electrode 15, however, a tin oxide material prepared by adding a
dopant to tin oxide (SnO.sub.2), or a zinc oxide material prepared
by adding a dopant to zinc oxide (ZnO) may be used in addition to
ITO. Examples of the zinc oxide material include aluminum zinc
oxide (AZO) added with aluminum (Al) as a dopant, gallium zinc
oxide (GZO) added with gallium (Ga), and indium zinc oxide (IZO)
added with indium (In). In addition, it is possible to use IGZP,
CuI, InSbO.sub.4, ZnMgO, CuInO.sub.2, MgIn.sub.2O.sub.4, CdO,
ZnSnO.sub.3, etc. Note that, in a case where the signal charges are
read from the first electrodes 13, the electric charges extracted
from the second electrode 15 are discharged through a wiring 114.
Therefore, the second electrode 15 is continuously formed as an
electrode common to the pixels P. The second electrode 15, however,
may be separated for each of the pixels.
[0054] The wiring 114 includes one or more of, for example,
tungsten (W), titanium (Ti), titanium nitride (TiN), and aluminum
(Al).
[0055] Note that a lower buffer layer may be formed between the
first electrodes 13 and the organic photoelectric conversion film
14, and an upper buffer layer may be formed between the organic
photoelectric conversion film 14 and the second electrode 15. Each
of the lower buffer layer and the upper buffer layer contains, for
example, an organic semiconductor material used in the organic
photoelectric conversion film 14, and functions as, for example, an
electron blocking film, a hole blocking film, or a work function
adjustment film.
[0056] In the present embodiment, the organic photoelectric
conversion film 14 includes an inclined surface t1 (first inclined
surface) on a side wall 140. In other words, the organic
photoelectric conversion film 14 includes a tapered shape (forward
tapered shape) tapered from the first electrodes 13 toward the
second electrode 15. The second electrode 15 includes an inclined
surface t2 (second inclined surface) on its side wall 150. An
inclination angle a1 of the inclined surface t1 and an inclination
angle a2 of the inclined surface t2 may be equal to each other or
different from each other as described later. In this case, the
inclination angles a1 and a2 are equal to each other. Further, the
inclined surface t2 is provided continuously to, for example, the
inclined surface t1 of the organic photoelectric conversion film
14.
[0057] FIG. 2 illustrates relationship between the inclination
angle a1 of the organic photoelectric conversion film 14 and
sealing property. The sealing property is evaluated with use of TDS
(Thermal Desorption Spectrometry) in which a sealing film is formed
to cover an LTO (Low Temperature Oxide) film and an amount of water
(H.sub.2O) desorbed from the LTO film through the sealing film is
measured. As illustrated, the sealing property is drastically
lowered at the inclination angle a1 of about 90 degrees, and in a
case where the inclination angle a1 exceeds 90 degrees (in a case
where a shape of organic photoelectric conversion film 14 becomes a
reversed tapered shape), the sealing property is not sufficiently
secured. This is because, although it is possible to form the first
sealing film 16 through, for example, the CVD method, the ALD
method, or the PVD method, film quality in a portion covering the
side wall 140 of the first sealing film 16 is largely deteriorated
due to the low-temperature process, which easily results in a
sparse film in the case where the CVD method or the ALD method of
these methods is used, and it is not possible for the first
insulation film 16 to cover the side wall 140 in principle in a
case where the PVD method is used. For the reason, the inclination
angle a1 of the side wall 140 of the organic photoelectric
conversion film 14 is set lower than 90 degrees, namely, the side
wall 140 of the organic photoelectric conversion film 14 has the
inclined surface t1.
[0058] For example, the inclined surfaces t1 and t2 are desirably
formed through collective (or continuous) processing of the organic
photoelectric conversion film 14 and the second electrode 15 in a
manufacturing process described later. The first sealing film 16 is
formed to cover the side wall 140 of the organic photoelectric
conversion film 14 and the second electrode 15 (specifically, a top
surface and the side wall 150 of the second electrode 15).
[0059] The first sealing film 16 has a function of suppressing
infiltration (penetration) of moisture to the inside of each of the
pixels P, specifically, to the organic photoelectric conversion
film 14. The first sealing film 16 contains one or more of
inorganic materials such as silicon oxide (SiO.sub.2), silicon
nitride (SiN), silicon oxynitride (SiON), and aluminum oxide
(AlO.sub.3). In the present embodiment, the first sealing film 16
is formed in contact with the side wall 140 of the organic
photoelectric conversion film 14. Therefore, as illustrated in FIG.
3, a sufficient distance d1 is desirably secured between an
effective pixel region 10A and a film formation region 10B of the
first sealing film 16. This makes it possible to reduce influence
on the organic photoelectric conversion film 14 formed in the
effective pixel region 10A in the formation process of the first
sealing film 16. The first sealing film 16 is formed with use of,
for example, an Atomic Layer Deposition (ALD) method, a Chemical
Vapor Deposition (CVD) method, or a Physical Vapor Deposition
method.
Manufacturing Method
[0060] FIG. 4 is a flowchart to explain main processes in a method
of manufacturing the solid-state imaging device 1. As illustrated,
the semiconductor substrate 11 is first formed (step S11).
Specifically, a so-called SOI substrate (not illustrated) that
includes the semiconductor layer 11a on a silicon base material
with a silicon oxide layer in between is prepared, and the wirings
111 including the above-described material are formed in the
semiconductor layer 11a. Thereafter, for example, the photoelectric
conversion devices 110B and 110B respectively including a p-type
region and an n-type region, and the charge accumulation layer 112
are formed in regions different in depth in the semiconductor layer
11a (so as to overlap with one another) through, for example, ion
injection. Further, the pixel transistors such as the transfer
transistor and the peripheral circuits such as the logic circuit
are formed on the front surface (surface S2) of the semiconductor
layer 11a. The multilayer wiring layer 11b including a plurality of
wirings 113 is formed on the surface S2 of the semiconductor layer
11a. Subsequently, the supporting substrate 11c is bonded to one
surface of the multilayer wiring layer 11b, and the silicon base
material and the silicon oxide layer are then peeled off from the
SOI substrate, to expose the surface S1 of the semiconductor layer
11a.
[0061] Next, the first electrodes 13 are formed on the
semiconductor substrate 11 with the interlayer insulation film 12
in between (step S12). Specifically, a hafnium oxide film
(insulation film 121) is first formed on the surface S1 of the
semiconductor substrate 11 through, for example, the ALD (atomic
layer deposition) method, and then the insulation film 122 and the
first electrodes 13 are formed. The insulation film 122 is formed
with use of silicon oxide through, for example, a plasma CVD
(Chemical Vapor Deposition) method. At this time, the insulation
film 122 is formed in a region between the first electrodes 13, and
the front surface thereof is planarized through, for example, a CMP
(Chemical Mechanical Polishing) method, which makes it possible to
electrically separate the first electrodes 13 from one another. The
first electrodes 13 are formed through film formation of the
above-described material with use of, for example, a sputtering
method, then patterning with use of photolithography technique,
followed by processing with use of dry etching or wet etching. Note
that the first electrodes 13 and the wirings 111 may be patterned
in an optional order.
[0062] Subsequently, the organic photoelectric conversion film 14
is formed (step S13). Specifically, the organic photoelectric
conversion film 14 is formed by depositing an organic semiconductor
material including the above-described material on the first
electrodes 13 through, for example, a vacuum vapor deposition
method. Note that, as the vacuum vapor deposition method, it is
possible to use, for example, an electron beam heating system and a
resistance heating system. In addition, the lower buffer layer, the
upper buffer layer, etc. may be formed as necessary. Furthermore,
the film formation method of the organic photoelectric conversion
film 14 is not limited to the vacuum vapor deposition method, and a
coating method may be used.
[0063] Next, the second electrode 15 is formed (step S14). The
characteristics of the organic photoelectric conversion film 14 are
typically largely varied due to influence of moisture, oxygen,
hydrogen, etc. Therefore, the second electrode 15 is desirably
formed in vacuum, together with the organic photoelectric
conversion film 14. It is possible to form the second electrode 15
by, for example, a vacuum vapor deposition method or a sputtering
method.
[0064] Subsequently, the formed organic photoelectric conversion
film 14 and the formed second electrode 15 are processed (step
S15). Specifically, patterning is performed with use of, for
example, photolithography technique, and then the second electrode
15 and the organic photoelectric conversion film 14 are
collectively processed through, for example, dry etching.
Thereafter, processing such as ashing is performed to remove
deposits and residues. Note that, in this case, the organic
photoelectric conversion film 14 and the second electrode 15 are
formed, and are then processed with use of photolithography and dry
etching; however, the formation method of the organic photoelectric
conversion film 14 and the second electrode 15 is not limited
thereto. It is possible to form, for example, the organic
photoelectric conversion film 14 and the second electrode 15 by
pattern formation with use of a shadow mask, etc.
[0065] As a result, the inclined surfaces t1 and t2 are
respectively formed on the side wall 140 of the organic
photoelectric conversion film 14 and the side wall 150 of the
second electrode 15. Note that adjusting conditions of the etching
makes it possible to form the side walls 140 and 150 such that the
inclination angles a1 and a2 of the inclined surfaces t1 and t2 are
equal to or different from each other.
[0066] Thereafter, the first sealing film 16 is formed (step S16).
Specifically, the first sealing film 16 including the
above-described material is formed with use of a film formation
method using low-temperature process, such as the CVD method, the
ALD method, and the PVD method. As a result, the side wall 140 of
the organic photoelectric conversion film 14 and the second
electrode 15 are covered with the first sealing film 16.
Thereafter, the wiring 114 electrically coupled to the second
electrode 15 is formed. Finally, although not illustrated, the
planarization film, the on-chip lens, etc. are formed. This results
in the solid-state imaging device 1 illustrated in FIG. 1.
Effects
[0067] In the solid-state imaging device 1 as described above, in a
case where light enters the organic photoelectric conversion film
14 through the first sealing film 16 and the second electrode 15, a
portion of the entering light (e.g., green light) is selectively
absorbed. As a result, in the organic photoelectric conversion film
14, electron-hole pairs are generated (photoelectric conversion is
performed), and one of the electrons and the holes are collected,
for example, on the first electrodes 13 side and are accumulated in
the charge accumulation layers 112 in the semiconductor substrate
11. The electric charges accumulated in the charge accumulation
layers 112 are read out as the electric signal to the peripheral
circuits through the transfer transistor Tr. In contrast, light
having passed through the organic photoelectric conversion film 14
(e.g., blue light and red light) is sequentially absorbed by the
photoelectric conversion devices 110B and 110R in the semiconductor
substrate 11 and is photoelectrically converted, and is read out as
an electric signal for each color.
[0068] In this case, in the solid-state imaging device 1 having the
above-described organic photoelectric conversion film 14, the first
sealing film 16 that covers the plurality of pixels P is formed in
order to prevent moisture from infiltrating into the pixels P.
Further, the organic photoelectric conversion film 14 is weak to
heat. Therefore, the first sealing film 16 is desirably formed
through a film formation method (such as CVD method, ALD method,
and PVD method) using a low-temperature process.
[0069] In a case where any of these film formation methods is used,
however, coverage of the film is not favorable, which makes the
first sealing film 16 difficult to exert sufficient sealing
performance in particular on the side wall of the organic
photoelectric conversion film 14. FIG. 5 illustrates a
configuration of a main part of a solid-state imaging device 100
according to a comparative example. As illustrated, in the
solid-state imaging device 100 according to the comparative
example, first electrodes 102, an organic photoelectric conversion
film 103, and a second electrode 104 are formed in this order on an
interlayer insulation film 101 as with the solid-state imaging
device 1 according to the present embodiment. A sealing film 105 is
formed to cover the organic photoelectric conversion film 103 and
the second electrode 104. A wiring 106 that is electrically coupled
to the second electrode 104 is formed on the sealing film 105. A
side wall 1030 of the organic photoelectric conversion film 103,
however, does not include an inclined surface and is perpendicular
to a substrate surface. In such a configuration, in a case where
the sealing film 105 is formed through, for example, the CVD
method, the ALD method, the PVD method, or the like described
above, coverage of the side wall 1030 of the organic photoelectric
conversion film 103 is deteriorated. Specifically, film quality of
the sealing film 105 is deteriorated or unevenness of a film
thickness occurs with respect to the side wall 1030 of the organic
photoelectric conversion film 103. A so-called notched (concave)
shape X11, a reversed tapered shape X12, etc. are generated, which
makes moisture easy to infiltrate from the side wall 1030. As a
result, photoelectric conversion characteristics of the organic
photoelectric conversion film 103 are deteriorated.
[0070] In contrast, in the present embodiment, the organic
photoelectric conversion film 14 includes the inclined surface t1
on the side wall 140. Therefore, even in the case where the first
sealing film 16 is formed through, for example, the CVD method, the
ALD method, the PVD method, or the like, coverage of the first
sealing film 16 to the side wall 140 is improved. Specifically, it
is difficult to form the notched shape X11 and the reversed tapered
shape X12 described above in a portion facing the side wall 140 of
the first sealing film 16, which makes it possible to cover the
side wall 140 with the first sealing film 16 having a uniform
thickness and favorable film quality. This makes it possible to
suppress infiltration of moisture from the side wall 140 of the
organic photoelectric conversion film 14.
[0071] Further, in the present embodiment, the second electrode 15
includes the inclined surface t2 on the side wall 150. Therefore,
as compared with a case where the side wall 150 of the second
electrode 15 does not include the inclined surface t2 (is a
perpendicular surface), the material of the first sealing film 16
is easily adhered to the organic photoelectric conversion film 14,
which makes it possible to improve sealing performance of the first
sealing film 16.
[0072] As described above, in the present embodiment, in the
plurality of pixels P, the organic photoelectric conversion film 14
includes the inclined surface t1 on the side wall 140, and the
first sealing film 16 that covers the side wall 140 of the organic
photoelectric conversion film 14 and the second electrode 15 is
formed on the plurality of pixels P. Accordingly, coverage of the
first sealing film 16 is improved in the portion facing the side
wall 140 of the organic photoelectric conversion film 14, which
makes it possible to suppress infiltration of moisture to the
organic photoelectric conversion film 14 from the side wall 140.
Therefore, it is possible to secure sealing performance to suppress
deterioration of the photoelectric conversion characteristics.
[0073] Next, other embodiments and modification examples of the
above-described first embodiment are described. In the following,
components similar to those of the above-described first embodiment
are denoted by the same reference numerals and description of such
components is appropriately omitted.
Modification Examples 1-1 and 1-2
[0074] FIG. 6A schematically illustrates a configuration of the
organic photoelectric conversion film 14 and the second electrode
15 of a solid-state imaging device according to a modification
example 1-1 of the above-described first embodiment. FIG. 6B
schematically illustrates a configuration of the organic
photoelectric conversion film 14 and the second electrode 15 of a
solid-state imaging device according to a modification example 1-2.
In the above-described first embodiment, the case where the
inclination angle a1 of the inclined surface t1 of the organic
photoelectric conversion film 14 and the inclination angle a2 of
the inclined surface t2 of the second electrode 15 are equivalent
to each other has been described; however, the inclination angles
a1 and a2 may be different from each other. In particular, the
inclination angle a2 is desirably equal to the inclination angle a1
or smaller than the inclination angle a1 as illustrated in FIG. 6A
(inclination angle a2 is desirably an angle equal to or lower than
inclination angle a1), which makes it possible to enhance sealing
performance of the first sealing film 16. Further, an allowable
range for the inclination angle a2 is less than 90 degrees, and the
inclination angle a2 may be larger than the inclination angle a1 as
illustrated in FIG. 6B.
Modification Example 2
[0075] FIG. 7 schematically illustrates a configuration of a main
part of a solid-state imaging device according to a modification
example 2 of the above-described first embodiment. In the
above-described first embodiment, the configuration in which the
organic photoelectric conversion film 14 is continuously formed as
the layer common to the plurality of pixels P (plurality of first
electrodes 13) has been exemplified; however, the organic
photoelectric conversion film 14 may be separated for each of the
pixels P as in the present modification example. As described
above, in the present modification example, the plurality of
organic photoelectric conversion films 14 are provided
corresponding to the first electrodes 13. Even in this case, each
of the organic photoelectric conversion films 14 includes the
inclined surface t1 on the side wall 140, which makes it possible
to improve sealing performance of the first sealing film 16.
Therefore, it is possible to achieve effects similar to those of
the above-described first embodiment.
Second Embodiment
[0076] FIG. 8 illustrates a cross-sectional configuration of a
solid-state imaging device according to a second embodiment of the
present disclosure. The solid-state imaging device of the present
embodiment is also applied to, for example, a CCD or CMOS image
sensor, etc. as with the above-described first embodiment, and
includes the plurality of pixels P two-dimensionally arranged. Each
of the pixels P includes the first electrode 13, the organic
photoelectric conversion film 14, and the second electrode 15 on
the semiconductor substrate 11 (substrate) with the interlayer
insulation film 12 in between. The first sealing film 16 (first
sealing film) that covers the organic photoelectric conversion film
14 and the second electrode 15 is formed on the plurality of pixels
P. The organic photoelectric conversion film 14 is formed above the
semiconductor substrate 11, and the photoelectric conversion
devices 110B and 110R are formed in the semiconductor substrate 11.
In one pixel P, the stacked-layer structure of the organic
photoelectric conversion film 14 and the photoelectric conversion
devices 110B and 110R makes it possible to disperse, for example,
color light of red (R), green (G), and blue (B) without using a
color filter, and it is possible to obtain a plurality of kinds
(here, three kinds of R, G, and B) of color signals from one pixel
P.
[0077] In the present embodiment, however, a second sealing film 17
is formed between the side wall 140 of the organic photoelectric
conversion film 14 and the first sealing film 16 unlike the
above-described first embodiment. The second sealing film 17
functions as a so-called side wall, and is formed in contact with
the side wall 140 of the organic photoelectric conversion film 14
and the side wall 150 of the second electrode 15. The second
sealing film 17 contains one or more of inorganic materials, a film
of which is formable through, for example, the PVD method, such as
silicon nitride, silicon oxide, and silicon oxynitride. The
constituent material of the second sealing film 17 may be the same
as or different from the constituent material of the first sealing
film 16.
[0078] Note that FIG. 8 illustrates the configuration in which the
side wall 140 of the organic photoelectric conversion film 14 and
the side wall 150 of the second electrode 15 are inclined (have
inclined surfaces). The second sealing film 17 and the first
sealing film 16 may be formed to cover the side wall 140 having the
inclined surface as with the above-described first embodiment,
which makes it possible to enhance sealing performance, as compared
with the above-described first embodiment.
[0079] As described above, in the present embodiment, the second
sealing film 17 is interposed between the side wall 140 of the
organic photoelectric conversion film 14 and the first sealing film
16, which suppresses infiltration of moisture to the organic
photoelectric conversion film 14 from the side wall 140. Therefore,
it is possible to achieve effects similar to those of the
above-described first embodiment.
[0080] Further, providing the second sealing film 17 makes it
possible to reduce damage to the organic photoelectric conversion
film 14 in the formation of the first insulation film 16. This
makes it possible to effectively suppress deterioration of the
photoelectric conversion characteristics.
Modification Examples 3-1 to 3-3
[0081] FIG. 9A schematically illustrates a configuration of a main
part of a solid-state imaging device according to a modification
example 3-1 of the above-described second embodiment. In the
above-described second embodiment, the configuration in which the
side wall 140 of the organic photoelectric conversion film 14 and
the side wall 150 of the second electrode 15 are inclined (have
inclined surfaces) has been described; however, the side walls 140
and 150 may not be inclined (may be perpendicular to the substrate
surface) as in the present modification example. This is because
interposition of the second sealing film 17 makes it possible to
enhance sealing performance even if the side wall 140 is
perpendicular. As described above, however, the second sealing
films 17 and the first sealing film 16 are desirably formed to
cover the side wall 140 having the inclined surface because sealing
performance is enhanced.
[0082] FIG. 9B schematically illustrates a configuration of a main
part of a solid-state imaging device according to a modification
example 3-2 of the above-described second embodiment. In the
above-described second embodiment, the configuration in which the
organic photoelectric conversion film 14 is continuously formed as
the layer common to the plurality of pixels P (the plurality of
first electrodes 13) has been exemplified; however, the organic
photoelectric conversion film 14 may be separated for each of the
pixels P as in the present modification example. In the present
modification example, the plurality of organic photoelectric
conversion films 14 are provided corresponding to the first
electrodes 13. Even in this case, the second sealing films 17 are
formed to cover the side walls 140 of the respective organic
photoelectric conversion films 14, which makes it possible to
improve sealing performance of the solid-state imaging device, and
to achieve effects similar to those of the above-described first
embodiment.
[0083] FIG. 9C schematically illustrates a configuration of a main
part of a solid-state imaging device according to a modification
example 3-3 of the above-described second embodiment. In the
configuration in which the plurality of organic photoelectric
conversion films 14 are formed separately for the respective pixels
P and each have the inclined surface t1 on the side wall 140, the
second sealing films 17 may be formed to cover the respective side
walls 140, as in the present modification example.
Third Embodiment
[0084] FIG. 10 illustrates a cross-sectional configuration of a
solid-state imaging device according to a third embodiment of the
present disclosure. The solid-state imaging device of the present
embodiment is also applied to, for example, a CCD or CMOS image
sensor, etc., as with the above-described first embodiment, and
includes the plurality of pixels P two-dimensionally arranged. Each
of the pixels P includes the first electrode 13, the organic
photoelectric conversion film 14, and the second electrode 15 on
the semiconductor substrate 11 (substrate) with the interlayer
insulation film 12 in between. The first sealing film 16 (first
sealing film) that covers the organic photoelectric conversion
films 14 and the second electrodes 15 is formed on the plurality of
pixels P. The organic photoelectric conversion films 14 are
provided above the semiconductor substrate 11, and the
photoelectric conversion devices 110B and 110R are formed in the
semiconductor substrate 11. In one pixel P, the stacked-layer
structure of the organic photoelectric conversion film 14 and the
photoelectric conversion devices 110B and 110R makes it possible to
disperse, for example, color light of red (R), green (G), and blue
(B) without using a color filter, and it is possible to obtain a
plurality of kinds (here, three kinds of R, G, and B) of color
signals from one pixel P.
[0085] In the present embodiment, however, the plurality of organic
photoelectric conversion films 14 are formed separately for the
respective pixels P unlike the above-described first embodiment.
The organic photoelectric conversion films 14 are formed for the
respective pixels P by selectively removing, for example, a region
between the pixels P through, for example, dry etching. FIG. 10
illustrates a region corresponding to selective two pixels in the
solid-state imaging device. In the present embodiment, a third
sealing film 18 is formed in a region between the side walls 140 of
the organic photoelectric conversion films 14 adjacent to each
other. The second electrodes 15 are formed corresponding to the
organic photoelectric conversion films 14 for the respective pixels
P. The wirings 114 are provided for the respective second
electrodes 15.
[0086] The third sealing film 18 is formed so as to fill the region
(recessed portion) between the side walls 140. The third sealing
film 18 is to prevent moisture from infiltrating into the organic
photoelectric conversion films 14 as with the first sealing film
16. For example, the third sealing film 18 contains the constituent
material of the first sealing film 16 (such as silicon oxide,
silicon nitride, and silicon oxynitride), or contains one or more
of aluminum oxide (AlO.sub.x), carbon-containing silicon oxide
(SiOC), tungsten (W), and aluminum (Al). As the constituent
material of the third sealing film 18, the material same as the
material of the first sealing film 16 may be selected; however, a
material having a refractive index lower than that of the first
sealing film 16 (e.g., an inorganic material or metal having a low
refractive index) is desirably selected. Specifically, for example,
one or more of aluminum oxide (AlO.sub.x), carbon-containing
silicon oxide (SiOC), tungsten (W), and aluminum (Al) are desirably
used for the third sealing film 18. This is because the material
allows the third sealing film 18 to function as a reflection film
and enhances light collection efficiency for each of the pixels
P.
[0087] As described above, in the present embodiment, the third
sealing film 18 is formed in the region between the side walls 140
of the organic photoelectric conversion films 14 adjacent to each
other, which suppresses infiltration of moisture to the organic
photoelectric conversion films 14 through the side walls 140 even
in the case where the plurality of organic photoelectric conversion
films 14 are formed separately for the respective pixels. This
makes it possible to achieve effects similar to those of the
above-described first embodiment.
[0088] Further, in the present embodiment, the third sealing film
18 includes the material having the refractive index lower than
that of the first sealing film 16 to function as the reflection
film, which makes it possible to enhance light collection
efficiency for each of the pixels P. This also makes it possible to
improve sensitivity.
[0089] Note that, in the above-described third embodiment, the side
walls 140 of the organic photoelectric conversion films 14 and the
side walls 150 of the second electrodes 15 may be inclined or not
be inclined (may be perpendicular to the substrate surface). This
is because the third sealing film 18 makes it possible to enhance
sealing performance to the side walls 140 even if the side walls
140 are perpendicular. However, forming the third sealing film 18
in the region between the side walls 140 each having the inclined
surface makes it possible to further enhance the sealing
performance.
Modification Example 4
[0090] FIG. 11 illustrates a cross-sectional configuration of a
solid-state imaging device according to a modification example 4.
In the present modification example, in the configuration in which
the plurality of organic photoelectric conversion films 14 are
provided separately for the respective pixels P, each of second
electrodes (second electrodes 15A) is continuously formed over a
region facing the top surface and a region facing the side wall 140
of each of the organic photoelectric conversion films 14. Moreover,
in the present modification example, the second electrodes 15A are
formed for the respective pixels P so as to cover the respective
organic photoelectric conversion films 14. The wirings 114 are
provided for the respective second electrodes 15A.
[0091] The present modification example illustrates a configuration
in which the side walls 140 of the organic photoelectric conversion
films 14 and the side walls 150 of the second electrodes 15 are
inclined (each have inclined surface). Each of the second
electrodes 15A is formed to cover the side wall 140 having the
inclined surface as with the above-described first embodiment. In
other words, each of the second electrodes 15A is interposed
between the side wall 140 of the organic photoelectric conversion
film 14 and the first sealing film 16.
[0092] As described above, the second electrodes 15A may cover the
side walls 140 of the respective organic photoelectric conversion
films 14 in the configuration in which the organic photoelectric
conversion films 14 are separated for the respective pixels P. This
makes it possible to allow the second electrodes 15A to function as
the sealing films, and to suppress infiltration of moisture to the
organic photoelectric conversion films 14 from the side walls 140.
Accordingly, it is possible to achieve effects similar to those in
the above-described first embodiment, etc.
[0093] Not that, even in the above-described modification example
4, the side walls 140 of the organic photoelectric conversion films
14 and the side walls 150 of the second electrodes 15 may be
inclined or not be inclined (may be perpendicular to the substrate
surface). This is because interposition of the second electrodes
15A makes it possible to enhance sealing performance to the side
walls 140 even if the side walls 140 are perpendicular. However,
forming the second electrodes 15A to cover the side walls 140 each
having the inclined surface makes it possible to further enhance
the sealing performance.
Modification Example 5
[0094] FIG. 12 illustrates a cross-sectional configuration of a
solid-state imaging device according to a modification example 5.
In the present modification example, in the configuration in which
the plurality of organic photoelectric conversion films 14 are
formed separately for the respective pixels P, a second electrode
(second electrode 15B) is continuously provided over the region
facing the top surface and the region facing the side wall 140 of
each of the organic photoelectric conversion films 14. In addition,
in the present modification example, the second electrode 15B is
continuously formed as a layer common to the plurality of pixels P
(the plurality of organic photoelectric conversion films 14), so as
to cover the organic photoelectric conversion films 14.
[0095] The present modification example illustrates a configuration
in which the side walls 140 of the organic photoelectric conversion
films 14 are inclined (have inclined surfaces). The second
electrode 15B is formed to cover the side walls 140 each having the
inclined surface as with the above-described first embodiment. In
other words, the second electrode 15B is interposed between the
side walls 140 of the organic photoelectric conversion films 14 and
the first sealing film 16.
[0096] As described above, the second electrode 15B may cover the
side walls 140 of the organic photoelectric conversion films 14 in
the configuration in which the organic photoelectric conversion
films 14 are separated for the respective pixels P. This makes it
possible to allow the second electrode 15B to function as the
sealing film, and to suppress infiltration of moisture to the
organic photoelectric conversion films 14 from the side walls 140.
Accordingly, it is possible to achieve effects similar to those in
the above-described first embodiment, etc.
[0097] Note that, even in the above-described modification example
5, the side walls 140 of the organic photoelectric conversion films
14 may be inclined or not be inclined (may be perpendicular to the
substrate surface). This is because interposition of the second
electrode 15B makes it possible to enhance sealing performance to
the side walls 140 even if the side walls 140 are perpendicular.
However, forming the second electrode 15B to cover the side walls
140 each having the inclined surface makes it possible to further
enhance the sealing performance.
Application Example 1
[0098] FIG. 13 illustrates a functional configuration of an imaging
apparatus 2 in which the solid-state imaging device 1 described in
the above-described first embodiment, etc. is used in a pixel
section 10. The imaging apparatus 2 includes the pixel section 10
as an imaging region, and includes a circuit section 20 as a
peripheral circuit of the pixel section 10. The circuit section 20
includes, for example, a row scanner 131, a horizontal selector
133, a column scanner 134, and a system controller 132.
[0099] The pixel section 10 includes, for example, the plurality of
pixels P that are two-dimensionally arranged in a matrix. For
example, a pixel driving line Lread (e.g., a row selection line and
a reset control line) is wired for each pixel row of the pixels P,
and a vertical signal line Lsig is wired for each pixel column of
the pixels P. The pixel drive line Lread transmits a driving signal
to read out signals from the pixels P. One end of the pixel drive
line Lread is coupled to an output end corresponding to each row of
the row scanner 131.
[0100] The row scanner 131 is a pixel driver that includes, for
example, a shift register, an address decoder, etc., and drives the
respective pixels P of the pixel section 10, for example, on a row
basis. The signals outputted from the respective pixels P on the
pixel row selectively scanned by the row scanner 131 are supplied
to the horizontal selector 133 through the respective vertical
signal lines Lsig. The horizontal selector 133 includes, for
example, an amplifier, a horizontal selection switch, etc. that are
provided for each vertical signal line Lsig.
[0101] The column scanner 134 includes, for example, a shift
register, an address decoder, etc., and sequentially drives the
horizontal selection switches of the horizontal selector 133 while
performing scanning. Through selection scanning performed by the
column scanner 134, signals of the respective pixels transmitted
through the respective vertical signal lines Lsig are sequentially
outputted to the horizontal signal line 135, and are transmitted to
outside of the semiconductor substrate 11 through the horizontal
signal line 135, or are provided to an unillustrated signal
processor.
[0102] In the imaging apparatus 2, for example, a substrate 2A
including the pixel section 10 and a substrate 2B including the
circuit portion (signal processing circuit) that includes the row
scanner 131, the horizontal selector 133, the column scanner 134,
the horizontal signal line 135, etc., are stacked as illustrated in
FIG. 14. The configuration, however, is not limited thereto, and
the above-described circuit portion may be formed on the same
substrate as the pixel section 10, or may be disposed on an
external control IC. Further, the circuit portion may be formed on
the other substrate that is coupled through a cable, etc.
[0103] The system controller 132 receives a clock provided from
outside, data instructing an operation mode, etc., and outputs data
such as internal information of the solid-state imaging device 1.
The system controller 132 further includes a timing generator that
generates various kinds of timing signals, and performs driving
control of peripheral circuits such as the row scanner 131, the
horizontal selector 133, and the column scanner 134, on the basis
of the various kinds of timing signals generated by the timing
generator.
Application Example 2
[0104] The above-described solid-state imaging device 1 is
applicable to all types of electronic apparatuses including an
imaging function, for example, a camera system such as a digital
still camera and a video camera, and a mobile phone including an
imaging function. FIG. 15 illustrates a schematic configuration of
an electronic apparatus 3 (camera) as an example. The electronic
apparatus 3 is, for example, a camera that is allowed to capture a
still image or a moving image, and includes the solid-state imaging
device 1, an optical system (optical lens) 310, a shutter unit 311,
a driver 313 that drives the solid-state imaging device 1 and the
shutter unit 311, and a signal processor 312.
[0105] The optical system 310 guides image light (entered light)
from an object to the solid-state imaging device 1. The optical
system 310 may include a plurality of optical lenses. The shutter
unit 311 controls a light irradiation period and a light shielding
period to the solid-state imaging device 1. The driver 313 controls
transfer operation of the solid-state imaging device 1 and shutter
operation of the shutter unit 311. The signal processor 312
performs various kinds of signal processing on the signals
outputted from the solid-state imaging device 1. An image signal
Dout subjected to the signal processing is stored in a storage
medium such as a memory, or outputted to a monitor, etc.
[0106] As described above, the present disclosure has been
described with reference to the embodiments and the modification
examples; however, the contents of the present disclosure are not
limited to the above-described embodiments, etc., and various
modification may be made. For example, the layer configuration of
the photoelectric conversion device described in the
above-described embodiments is illustrative, and may further
include other layers. In addition, the materials and the
thicknesses of the respective layers are also illustrative and are
not limited to those described above.
[0107] Further, in the above-described embodiments, etc., the
back-illuminated solid-state imaging device has been described as
an example; however, the solid-state imaging device of the present
disclosure is applicable to a front-illuminated device
structure.
[0108] Further, in the above-described embodiments, etc., as the
solid-state imaging device, the organic photoelectric conversion
film 14 detecting the green light and the photoelectric conversion
devices 110B and 110R respectively detecting the blue light and the
red light are stacked in one pixel; however, the contents of the
present disclosure is not limited to such a structure. In other
words, the organic photoelectric conversion film formed on the
substrate may detect red light or blue light, or a plurality of
kinds of organic photoelectric conversion films that respectively
photoelectrically converts color light of red, green, and blue may
be stacked. As described above, the number of the organic
photoelectric conversion films formed on the semiconductor
substrate, the number of photoelectric conversion devices formed in
the semiconductor substrate, and the combination thereof are not
particularly limited. In addition, the photoelectric conversion
devices of the respective colors may be two-dimensionally arranged
without limitation to the structure in which the plurality of
photoelectric conversion devices are stacked in one pixel.
Moreover, a color filter may be provided. The present disclosure is
applicable to all kinds of solid-state imaging devices including
the organic photoelectric conversion film.
[0109] Further, the effects described in the above-described
embodiments, etc. are illustrative, and other effects may be
achieved or other effects may be further included.
[0110] It is to be noted that the present disclosure may have the
following configuration.
(1)
[0111] A solid-state imaging device, including:
[0112] a plurality of pixels each including a first electrode, an
organic photoelectric conversion film, and a second electrode in
this order on a substrate, the organic photoelectric conversion
film including a first inclined surface on a side wall; and
[0113] a first sealing film formed, on the plurality of pixels, to
cover the side wall of the organic photoelectric conversion film
and the second electrode.
(2)
[0114] The solid-state imaging device according to (1), in
which
[0115] a plurality of the first electrodes are provided on the
substrate, and
[0116] the organic photoelectric conversion film is continuously
formed as a layer common to the plurality of first electrodes.
(3)
[0117] The solid-state imaging device according to (1) or (2), in
which the second electrode includes a second inclined surface on a
side wall thereof.
(4)
[0118] The solid-state imaging device according to (3), in which
the second inclined surface has an inclination angle equal to or
lower than an inclination angle of the first inclined surface.
(5)
[0119] The solid-state imaging device according to any one of (1)
to (4), in which the first sealing film is formed in contact with
the side wall of the organic photoelectric conversion film.
(6)
[0120] The solid-state imaging device according to any one of (1)
to (5), further including a second sealing film between the side
wall of the organic photoelectric conversion film and the first
sealing film.
(7)
[0121] The solid-state imaging device according to any one of (1)
to (6), in which
[0122] a plurality of the first electrodes and a plurality of the
organic photoelectric conversion films are formed, and
[0123] a third sealing film having a refractive index lower than a
refractive index of the first sealing film is further included in a
region between the side walls of the organic photoelectric
conversion films adjacent to each other.
(8)
[0124] The solid-state imaging device according to any one of (1)
to (7), in which the second electrode is continuously formed over a
region facing a top surface and a region facing the side wall of
the organic photoelectric conversion film.
(9)
[0125] The solid-state imaging device according to (8), in
which
[0126] a plurality of the first electrodes and a plurality of the
organic photoelectric conversion films are formed, and
[0127] the second electrode is provided for each of the organic
photoelectric conversion films.
(10)
[0128] The solid-state imaging device according to (8), in
which
[0129] a plurality of the first electrodes and a plurality of the
organic photoelectric conversion films are formed, and
[0130] the second electrode is continuously provided as a layer
common to the organic photoelectric conversion films.
(11)
[0131] The solid-state imaging device according to any one of (1)
to (10), in which the organic photoelectric conversion film
contains one or more of quinacridone, subphthalocyanine, or
derivatives thereof.
(12)
[0132] The solid-state imaging device according to any one of (1)
to (11), in which the substrate includes a semiconductor layer that
includes one or two or more photoelectric conversion devices.
(13)
[0133] A method of manufacturing a solid-state imaging device, the
method including:
[0134] a process of forming a plurality of pixels each including a
first electrode, an organic photoelectric conversion film, and a
second electrode in this order on a substrate, the organic
photoelectric conversion film including a first inclined surface on
a side wall; and
[0135] a process of forming a first sealing film, on the plurality
of pixels, to cover the side wall of the organic photoelectric
conversion film and the second electrode.
(14)
[0136] The method of manufacturing the solid-state imaging device
according to (13), in which
[0137] after the organic photoelectric conversion film and the
second electrode are formed in this order,
[0138] the formed organic photoelectric conversion film and the
formed second electrode are collectively processed to form the
first inclined surface on the side wall of the organic
photoelectric conversion film, and to form a second inclined
surface on a side wall of the second electrode.
(15)
[0139] The method of manufacturing the solid-state imaging device
according to (13) or (14), in which the first sealing film is
formed with use of an Atomic Layer Deposition (ALD) method, a
Chemical Vapor Deposition (CVD) method, or a Physical Vapor
Deposition (PVD) method.
(16)
[0140] A solid-state imaging device, including:
[0141] a plurality of pixels each including a first electrode, an
organic photoelectric conversion film, and a second electrode in
this order on a substrate;
[0142] a first sealing film formed, on the plurality of pixels, to
cover a side wall of the organic photoelectric conversion film and
the second electrode; and
[0143] a second sealing film formed between the side wall of the
organic photoelectric conversion film and the first sealing
film.
(17)
[0144] The solid-state imaging device according to (16), in which
the second sealing film is formed in contact with the side wall of
the organic photoelectric conversion film and a side wall of the
second electrode.
(18)
[0145] A solid-state imaging device, including:
[0146] a plurality of pixels each including a first electrode, an
organic photoelectric conversion film, and a second electrode in
this order on a substrate; and
[0147] a first sealing film formed on the plurality of pixels, in
which
[0148] a plurality of the organic photoelectric conversion films
are disposed separately for the respective pixels, and
[0149] a third sealing film is formed to fill a region between side
walls of the organic photoelectric conversion films adjacent to
each other.
(19)
[0150] The solid-state imaging device according to (18), in which
the third sealing film has a refractive index lower than a
refractive index of the first sealing film.
(20)
[0151] The solid-state imaging device according to (19), in which
the third sealing film contains one or more of aluminum oxide
(AlO.sub.x), carbon-containing silicon oxide (SiOC), tungsten (W),
and aluminum (Al).
(21)
[0152] An electronic apparatus provided with a solid-state imaging
device, the solid-state imaging device including:
[0153] a plurality of pixels each including a first electrode, an
organic photoelectric conversion film, and a second electrode in
this order on a substrate, the organic photoelectric conversion
film including a first inclined surface on a side wall; and
[0154] a first sealing film formed, on the plurality of pixels, to
cover the side wall of the organic photoelectric conversion film
and the second electrode.
[0155] This application claims the benefit of Japanese Priority
Patent Application JP2015-198578 filed on Oct. 6, 2015, the entire
contents of which are incorporated herein by reference.
[0156] It should be understood by those skilled in the art that
various modifications, combinations, sub-combinations, and
alterations may occur depending on design requirements and other
factors insofar as they are within the scope of the appended claims
or the equivalents thereof.
* * * * *